The invention relates to an automatic antilock control system for vehicles.
One such system comprises a sensor for determining a tendency of a vehicle wheel to lock, an evaluation circuit for processing the sensor signals and for producing control signals and a brake pressure control device with at least one magnetic valve, to which are fed these control signals for the variation of the brake pressure, wherein the evaluation device and the brake pressure control device are designed in such a manner that a pressure build-up with variable pressure gradients is possible.
Such an automatic antilock control system is known, for example, from German Accepted Patent Specification No. 1,166,012. In the case of this known automatic control system, throttle valves are provided in addition to an inlet and an outlet valve, so that a throttled pressure build-up and pressure reduction can be achieved in addition to a rapid pressure build-up and pressure reduction. The variable pressure gradients rendered effective as a result of the variable rotary behaviour of the wheel.
From the German Published Patent application No. 1,914,765 there is known an automatic antilock controller, in which the variable pressure gradients are realised on pressure build-up and/or reduction by open-loop control of the valves with pulses. In fact, this Published Patent application describes the possibility of producing such variable pressure gradients, but nothing is stated regarding the sequence of the application of these variable gradients.